--nav-toc=full is not full when topicrefs have no href

[TiboGr]

Expected Behavior

When using --nav-toc=full, the full toc should be in every output

Actual Behavior

The toc is not full, entries under a topicref without @href are not present

Steps to Reproduce

Use a bookmap with a following structure :
nav-toc.zip

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE bookmap PUBLIC "-//OASIS//DTD DITA BookMap//EN" "bookmap.dtd">
<bookmap>
    <booktitle>
        <mainbooktitle>Title</mainbooktitle>
    </booktitle>
    <frontmatter>
        <booklists>
            <toc/>
        </booklists>
    </frontmatter>
    <chapter>   
        <mapref href="map1.ditamap"/>    
    </chapter>
     <chapter href="chapter2.dita">   
        <mapref href="map2.ditamap"/>    
    </chapter>
    <backmatter/>
</bookmap>

1. run the following command : dita -i guide.bookmap -o out -f html5 --nav-toc=full
2. the toc is complete in index.html, however all entries for map1 are absent from the toc in the content files.

Environment

• DITA-OT version: 4.2.2
• Operating system and version: Windows 11
• How did you run DITA-OT? dita command
• Transformation type: HTML5